1. Field of the Invention
The invention relates to method and apparatus for characterizing a population of particles such as red blood cell typing for blood banking, while blood cell typing for histocompatibility or virus identification with specific antibodies, and other agents which bind with cells. The invention further relates to exploitation of specific cell receptors for analysis of the cells or samples reacting with the cells in an automatic analyzer.
2. Description of the Prior Art
In blood banking, the characteristics of red blood cells (blood typing) are usually determined by mixing a plurality of aliquots of the red cell suspension with different reagents and visually inspecting for agglomeration of cells. An automatic red cell typing system employing a flowing stream is manufactured by Technicon Corp. In this apparatus, the cell suspension is mixed with different reagents and the agglomerated cells are separated from disperse cells by decantation. Once again, the criterion of reaction is presence of agglomeration after mixing with a particular reagent.
In microbiology, organisms are generally characterized by their growth behavior in selected media. However, some identification is done by testing reaction with a panel of specific antibodies. The end point is often a form of precipitation. There are binding sites (receptors) on certain cells that are specific for certain ligands. These receptors are often the mechanism through which the ligand (often a hormone) performs its physiological functions. Cell receptor analysis often employs reaction of an aliquot of the cell population with radioactive ligand followed by separation of cell bound from free ligand. The radioactivity in one or both separated components is then measured. This is all done manually. The ligands are often vital hormones. Quantitation of both the ligand and the cell receptor are becoming important in clinical diagnosis. As the demand for such analysis increases, the manual procedure will give way to automation.